Clay - Pre-Operative Risk Assessment USAFP Apr2011 _FILEminimizer_

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					Pre-Operative Risk Assessment

       Emily Clay, MD, FAAFP
   Family Medicine Residency Faculty
   Martin Army Community Hospital,
             Ft. Benning
          USAFP Presentation
              April 2011
 Understand that we are not “clearing” a
  patient for surgery
 Recommendations for evaluation prior to
 Algorithm for risk-stratifying patients
 Risk-stratification of surgeries
 Medical recommendations
 Dr. X’s nurse at the Columbus Orthopedics
  clinic has paged you asking that your 89 yo
  male patient Jim Smith scheduled for right
  hip arthroplasty in 3 days be cleared for
 What is your response?
 How do you quickly assess this patient’s
 What tests and/or meds do you order?
Case, continued
 PMH: MI 1 yr ago- received
  antithrombolytics with resolution of
 No tobacco history, or h/o CVA or DM.
 Normal EF and renal function.
 Walks 2 miles in the morning for years,
  now limited last 4 months by hip pain
 Meds: HCTZ 25mg daily, Zocor 40mg
  daily, Aspirin 81mg daily, also ran out of
  Atenolol 25mg daily 2 weeks ago.
Case, continued
 Mr Smith’s vitals: 157/92, HR 70s, normal
  temp, RR, O2 sat. BMI 25.
 Normal physical exam
 EKG with Q waves inferiorly
Is the surgery an emergency?
 If condition requiring surgery is acutely life-
  threatening, then go straight to surgery,
  without further evaluation…
If surgery is not an emergency…
1- Assess patient risk factors for perioperative
   morbidity and mortality
2- Assess surgical risk

 This info will help determine:
   – Need for diagnostic testing
   – Measures to prepare higher risk patients for surgery
 Preoperative outpatient medical evaluation
   – May decrease length of hospital stay
   – May minimize postponed or cancelled surgeries.
          Preoperative History
 PMH, PSH, prior complications of surgery,
 Medication Reconciliation, Allergy Review
 Immunization Status
 Smoking, alcohol, drug use (stop smoking >8
  weeks prior to surgery)
 Social support (need any assistance after hospital
  stay, even a ride home from the hospital?)
Preoperative Physical Exam
 Vitals- height, weight, BMI, BP, HR, O2
  sat, RR, temp, pain scale.
 Cardiac exam: murmurs, gallops, signs of
  CHF, irregular rhythms, etc.
 Lung exam: signs of acute or chronic
  pulmonary disease.
 Signs of malnutrition
 Mental status exam (baseline)
Summary of Recommended
Preoperative Tests (pending H&P
 Healthy < age 40: CBC, Urine HCG
 Healthy > age 40: Add EKG and blood
Recommended Preoperative
Tests for Patients with Elevated
Cardiovascular Risk Factors
 Also:
  – If recent MI < 6 weeks, unstable angina,
    decompensated CHF, significant arrhythmias, severe
    valvular disease: CARDIOLOGY CONSULT
  – Previous MI> 6 weeks, mild stable angina,
    compensated CHF, DM: STRESS TEST, +/- ECHO
  – Rhythm other than NSR, h/o abnl EKG, h/o CVA,
    advanced age, or low functional capacity: STRESS
Summary of Recommended
Preoperative Tests for Patients
with Pulmonary Risk Factors
 CXR, CBC, CHEM, EKG, provide
  instructions for incentive spirometry or deep
  breathing exercises.
  –   Asthma: PFTs or PEAK FLOW
  –   COPD: PFT, ABG baseline
  –   Cough, dyspnea: Evaluate etiology
  –   Smoking: Counsel on tobacco cessation 8
      weeks prior to procedure.
Summary of Recommended
Preoperative Tests for Patients
with Other Risk Factors
 Obesity or Obstructive Sleep Apnea: Instruct
  patients on Incentive Spirometry or deep-
  breathing exercises
 Abdominal or thoracic surgery: Instruct patients
  on IS or deep-breathing
 Malnutrition: Labs based on primary disease
  (Cancers, HIV, etc), plus albumin (<3.2) and
  lymphocyte count (<3000).
   – Consider postponing surgery if severe
   – Provide nutritional supplementation pre- and post-op
    Cardiovascular Disease

 Affects 25% of the US population
 Leading cause of death in the US
 > 60% of CV deaths due to coronary disease
Perioperative Risk
 20-40% of patients at high risk of cardiac-
  related morbidity will develop myocardial
  ischemia perioperatively
 Of 27 million patients undergoing
  anesthesia annually in the U.S., 0.2% or
  50,000 will have a perioperative MI.

   Fleisher LA, Eagle KA. Clinical Practice. Lowering Cardiac risk in noncardiac surgery.
    N Eng J Med 2001; 345;1677-82
Perioperative Cardiac
 Approx 50% are due to postoperative
  ischemia or CHF
 Highest in first 48 hrs after surgery
 Ischemia may be silent in 90% of cases
Patient risk
 Clinical Predictors of Increased
  Perioperative Cardiovascular
- Unstable coronary syndromes (acute MI,
  severe angina)
- Decompensated heart failure
- Significant arrhythmias
- Severe valvular disease
  Clinical Predictors of Increased
   Perioperative Cardiovascular
- Mild angina
- Previous MI by history or pathologic Q
  waves on EKG
- Compensated or prior heart failure
- Diabetes mellitus (esp if on insulin)
- Renal insufficiency
 Clinical Predictors of Increased
  Perioperative Cardiovascular
- Advanced age (>75 yrs)
- Abnormal EKG results (LVH, LBBB, ST-T
  wave changes)
- Rhythm other than sinus (A fib)
- Low functional capacity (inability to climb
  one flight of stairs w/ bag of groceries)
- H/o CVA or uncontrolled systemic HTN
Surgical risk
  Procedures at HIGH risk for
 cardiac death and nonfatal MI
 (>5% chance of cardiac event)

- Emergent major operations, esp in pts >75
- Aortic and other major vascular surgery
- Peripheral vascular surgery
- Anticipated prolonged surgical procedure
  associated with large fluid shifts or blood
 Procedures at INTERMEDIATE
     risk for cardiac death and
            nonfatal MI
  (1-5% chance of cardiac event)
- Carotid endarterectomy
- Head and neck surgery
- Interperitoneal and intrathoracic surgery
- Orthopedic surgery
- Prostate surgery
   Procedures at LOW risk for
  cardiac death and nonfatal MI
  (<1% chance of cardiac event)
- Endoscopic procedures
- Superficial procedures
- Cataract surgery
- Breast surgery
 to surgery
  Goals of Perioperative Testing
- To measure functional capacity
- To identify the presence of myocardial
  ischemia or cardiac arrythmias
- To estimate cardiac risk
Positive predictive value
 -Proportion of patients with positive test results
 who are correctly diagnosed
 -Precision rate
Negative predictive value
 -Proportion of patients with a negative test
 result who are correctly diagnosed.
 - High NPV = when the test yields a negative
 result, it is uncommon that the result should
 have been positive
- Important predictor of perioperative risk and need
  for invasive monitoring
- Excellent exercise tolerance, even if pt has stable
  angina, suggests that the myocardium can be
  stressed without becoming dysfunctional.
- Suggested likelihood of complication inversely
  proportional to # of blocks that can be walked or
  flights of stairs climbed.
Exercise/ Stress Testing
 Reserved for moderate to high risk patients
  undergoing moderate to high risk surgery
 If testing has been done within 6 months of
  surgery, not necessary to repeat (unless new
  – Same if revascularization procedure done
    within 6 months, if no new symptoms
  Myocardial Perfusion Imaging
For patients undergoing Vascular Surgery:
- Positive predictive value (PPV) for
  ischemia of 4-20%
- NPV 95-100%
For patients undergoing NON-Vascular
- PPV for ischemia 8-67%
- NPV 98-100%
Dobutamine stress
echocardiogram testing
 PPV for ischemia 10-24%
 NPV for ischemia 98-100%

 Eagle KA, Berber PB, Calkins H, Chaitman BR, Ewy GA, Feischmann KE, et
   al. ACC/AHA guidelines update for perioperative cardiovascular evaluation
   for noncardiac surgery- an executive summary: a report of the ACC/ AHA
   Task Force on Practice Guidelines. J Am Coll Cardiol 2002; 39:542-53.
  Coronary Artery Revascularization
     Prophylaxis (CARP) Study-
         published Nov2004
- 5959 pts w/ CAD risk factors undergoing
 elective major vascular surgery assigned to
 2 groups
  - Received coronary art revascularization
    (i.e. percutaneous coronary intervention or
    bypass surgery) before surgery
  - Received no revascularization prior to surgery
- Study excluded pts with EF<20%, Left
 main coronary artery stenosis, or severe
 aortic stenosis
CARP Study
 Tested the hypothesis that coronary artery
  revascularization prior to elective surgery
  improves long-term survival.
 Multicenter, randomized, controlled,
  cooperative trial involving subjects from 18
  Veterans Affairs Medical Centers.
        CARP Study Outcome
30 days post-op: 12% pts in revascularization group
  and 14% pts in non-revascularization group
  suffered post-op MI
3 years post-op: 22% mortality in revascularization
  group and 23% in non-revascularization group

CONCLUSION: Coronary artery revascularization
 before elective vascular surgery on moderate-risk
 patients does NOT significantly alter the long-
 term outcome and cannot be recommended.
    Other Methods to Assess
          Cardiac Risk

- Goldman criteria (1977)
- Detsky’s clinical risk index (1986)
- Lee’s revised cardiac risk index (1999)
     Lee’s Revised Cardiac Risk
Clinical Variable
- High-risk surgery= 1 point
- Coronary artery disease= 1 point
- CHF= 1 point
- H/o CVA= 1 point
- Insulin tx for diabetes= 1 point
- Preop serum creatinine> 2.0mg/dl= 1 point

Lee TH. Circulation. 1999 Sep 7; 100(10): 1043-9
   Lee’s Revised Cardiac Risk
         Index- Scoring
Very Low Risk= 0 points
 (0.4% risk of complications)
Low Risk= 1 point
 (0.9% risk of complications)
Moderate Risk= 2 points
 (6.6% risk of complications)
High Risk= 3+ points
 (11% risk of complic)
Formula on smartphones (Medcalc, etc)
Medical Treatment to
Reduce Perioperative
         Meds to Reduce
   Perioper Risk: Beta Blockers
- Studies support the use of perioperative beta
  blockade to reduce c/v morbidity and mortality
  only in patients with known cardiovascular disease
  undergoing vascular surgery and in those already
  on beta blockers.
Beta Blockers
- Target heart rate in 60’s perioperatively
- Previous studies showed that perioperative beta
  blockade decreased risk of MI during and after
- 2 studies (POISE and DECREASE-IV)
- Usefulness less well-established in:
   - Pts with intermediate or high-risk procedures or
     vascular surgery who are low or intermediate in cardiac
     risk factors.
   - Pts with low cardiac risk not previously on beta
POISE Study- 2008
 Perioperative Ischemic Evaluation trial
 Large, randomized, controlled study of
  8000 patients from 23 countries, >age 45,
  increased cardiac risk, having noncardiac
 POISE showed:
  – MI risk was reduced in patients randomized to
    beta blockers
  – But they also had a HIGHER risk of stroke and
    death= net harm
  – Lancet, May 2008
POISE Study- 2008
 For every 1000 patients treated, metoprolol
  CR would prevent 15 MIs, but there would
  be an excess of 8 deaths and 5 severe
  disabling strokes.
 Did not address patients already on beta
 2009 AHA/ACC guidelines taskforce on
  beta blockade agree that these patients
  should remain on their beta blockers
  through surgery
          Meds to Reduce
        Perioper Risk: Statins
 Act via multiple mechanisms to improve
  atherosclerotic plaque stability and to
  inhibit leukocyte adhesion
 Current evidence provides support for
  statins in patients at high risk of
  perioperative mortality.
Statin Recommendations
 Class I: For patients currently taking statins
  and scheduled for noncardiac surgery, statins
  should be continued (Level of Evidence: B)
 Class Iia: For patients undergoing vascular
  surgery with or without clinical risk factors,
  statin use is reasonable. (Level of Evidence: B)
 Class Iib: For patients with at least 1 clinical
  risk factor who are undergoing intermediate-
  risk procedures, statins may be considered.
  (Level of Evidence: C)
        Meds to Reduce
 Perioper Risk: Alpha2-Agonists
-Number of studies suggest a reduction in the
  incidence of perioperative myocardial
  ischemia in patients undergoing vascular
- One recent study rec’s clonidine pill or patch
  started on morning prior to surgery and
  continued for 4 days postoperatively.
         Meds to Reduce
 Perioper Risk: Calcium Channel
      Blockers and Nitrates
- To date, no evidence that there are
  additional benefits from using these meds
  perioperatively to reduce risk.
Antiplatelet Therapy
 Continue aspirin preoperatively when used
  as secondary prevention of cardiovascuar
  disease & stroke
 Continue plavix after stent or MI for
  recommended timeframes due to risk for
  coronary stenosis

 Biondi-Zoccai GG, Lotrionte M, Agostoni P, et al. A systematic review and
   meta-analysis on the hazards of discontinuing or not adhering to aspirin among
   50,279 patients at risk for coronary artery disease. Eur Heart J.
Antiplatelet Therapy
 Risk of CV events when stopping
  antiplatelet therapy is higher than the risk of
  surgical bleeding when upholding them
 Elective operations should be delayed
  beyond dual antiplatelet therapy
 Operations on dual antiplatelet therapy
  should be continued without operation

   ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for
    noncardiac surgery: executive summary: a report of the American College of
    Cardiology/American Heart Association Task Force on Practice Guidelines
Types of Anesthesia
 Anesthesiologist to choose the type of
 General & epidural anesthesia may not
  differ significantly in rates of perioperative
  cardiac complications (studies conflict)
Key Recommendations for
 Beta blockers should be considered
  perioperatively to patients with known
  ischemic heart disease undergoing vascular
  surgery or who have previously taken beta
 BB are not recommended for patients with
  low to moderate risk of perioperative
  cardiovascular complications (Class B rec)
Key Recommendations for
Practice, continued
 Statin use is assoc w/ reduction in
  perioperative risk in patients with
  preexisting CAD, although randomized trial
  data are lacking (Class B rec)
 Alpha2-agonists (clonidine) are a possible
  alternative to beta blockers to reduce
  perioperative risk of cardiac complications
  in high-risk patients (Class B rec)
Case Discussion
 Hip arthroplasty= intermediate risk surgery
 Lee revised cardiac risk index= 1 point
  CAD (LOW RISK for perioperative cardiac
 Good functional status, so decided that
  stress testing not necessary
 Refill atenolol beta blockade that pt was on
 Continue statin therapy
 Continue aspirin therapy
1.   American College of Cardiology/American Heart Association (ACC/AHA)
     Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery,
     1996, updated 2002 and 2007.
2.   “Preparation of the Cardiac Patient for Noncardiac Surgery,” Flood and Fleisher,
     American Family Physician. 2007 Mar 1;75(5):656-665
3.   “Preoperative Cardiac Risk Assessment,” Karnath, American Family
     Physician. 2002 Nov 15;66(10):1889-1897
4.   “Preoperative Evaluation,” King, American Family Physician, July 15, 2000.
5.   “Cardiovascular Evaluation and Management of Severely Obese Patients undergoing
     surgery: A science advisory from the American Heart Association,” Poirier, et al,
     June 2009.
6.   “Cost-effective Preoperative Evaluation and Testing,” Fischer, American College of
     Chest Physicians, 1999; 115:96S-100S.
7.   “Perioperative Antiplatelet Therapy,” Chassot, Marcucci, et al, American Family
     Physician. 2010 Dec 15;82(12):1484-1489.
8.   “Safety of short-term discontinuation of antiplatelet therapy in patients with drug-
     eluting stents,” Eisenberg MJ, Richard PR, Libersan D, Filion KB . Circulation.
9.   Burger W, Chemnitius JM, Kneissl GD, Rücker G. Low-dose aspirin for secondary
     cardiovascular prevention - cardiovascular risks after its perioperative withdrawal
     versus bleeding risks with its continuation - review and meta-analysis. J Intern Med.

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